The Food and Drug Administration has received 51 reports of cases in the United States in which chemical peritonitis was associated with the intraperitoneal administration of sterile vancomycin hydrochloride, USP intravenous. The clinical presentation of the cases ranged from mild (cloudy dialysate alone) to more severe (severe abdominal pain and fever). The temporal circumstances suggest that intraperitoneal vancomycin may be associated with chemical peritonitis. A positive rechallenge was reported in 9 cases. The underlying mechanism responsible for this adverse reaction has not yet been identified.